Improvement in compound steam-engines



G. H. CORLISS. Compound Steam-Engine.

No. 215,799. Pate'medlvlay 27, 1879.

UNITE-D STATES PATENT OFFTcn,

GEORGE H. OORLISS, OF PROVIDENCE, RHODE ISLAND.

IMPROVEMENT IN COMPOUND STEAM-ENGINES.

Specification forming part of Letters Patent No. 215,799, dated May 27,1879 g application iiled October 28, 1878.

To all whom 'it may concern:

Be it known that 1 GEORGE H. OoRLIss, of Providence, in the State ofRhode Island, have invented certain new and useful Improvements relatingto Compound Steam-Engines; and I do hereby declare that the following isa full and exact description of the same.

It has been heretofore proposed to render the pressure in the secondcylinder approximately uniform up to the point of cut-G by employing anintermediate chamber, which I will term a receiver, of considerablecapacity. I do this and employ a variable cut-oft' on both the high andthe low pressure part of the apparatus. I provide means for varying thepoints of cut-off in both engines simultaneously, and can thereby varythe pressure gradually or rapidly within wide limits and still maint-ainthe desired ratio of the pressures or near it. I provide means also forvarying Jthe cut-oft' of one engine independently of the other. I can,by this means, change the ratio of the pressures; but there is alwaysamore or less active escape of heat from the intermediate chamber andfrom the pipes and passages. I clothe all these and preserve the hea-tas far as possible; and in addition to all this I provide a constantcircula-tion of the contents of the receiver, taking steam with whateverwater may be present from the lowest point in the receiver, circulatingit through the tubes, where it is exposed to spent heat from the boiler,and allowing it to return in a dry and more or less superheatedcondition in the top or side of the receiver. I attach much importanceto this latter provision as a means of insuring dry steam in the second,the largestor lowpressure cylinder.

The subject-matter of my present invention relates to the receiver andits connections, and the provisions for insuring a circulation of aportion of its contents,including all the water which collects thereinthrough a separate heating-surface,which may be at any distance and atany level desired.

By another provision I allow of the taking of any desired quantity ofsteam from the re-. ceiver after it has done its work in thehighpressure cylinder, and of using it for steamheating or for drying,or for any other purpose for which steam of a uniformly moderatepressure is desired.

The following is a description-of what I consider the best means ofcarrying out the invention. i

The accompanying drawings form a part of this specification.

Figure 1 is an elevation, and Fig. 2 is a plan vlew.

Similar letters of reference indicate like parts in both iigures.

A A are horizontal tubes extending from certain hollow castings B, whichserve as end connections 011 one side, to corresponding castings servingas end connections on the other side of a hot-chamber, m', whichreceives the products of combustion from. a series of boilers, M,through passages m. The gases containing whatever heat has not beenextracted in their` passage through the boilers seek the chimney bymoving horizontally through the interstices between the tubes A,

and thereby impart a further portion of their heat to whatever fluid maybe circulated through the tubes. The tubes are curved to better allowfor irregularities of expansion and contraction. They are, furthermore,formed with small ends a, so that their areas at the points ofconnection to the castings B are less than their areas at the otherpoints. This renders the apparatus more desirable as a heating means. Italso allows the pipes A to be placed more nearly together than would beotherwise expedient, and allows an adequate strength to the castings andall the parts. These peculiarities are made the subject of a separateapplication for Letters Patent. They are desirable, but not essential tothe success of the present invention. I will, when necessary', refer tothe heating-tubes A and their immediate connections B at each end as theheating apparatus.

The pipe marked D brings a constant supply ot' steam or water, or both,introducing it at a low point at one end of the heating apparatus. Thelarger pipe, E, conducts away a constant stream of dried and (under mostconditions) superheated steam from a high point at the other end of theheating apparatus.

I have in Fig. l represented the connections allows it to be drawn fromat the times re-` quired at the early part of each stroke in the10W-pressure cylinder, and the pressure therein is not much diminishedin consequence of the large drafts thereby made 3 nor, again, is thepressure much increased in consequence of the fluctuating receipt ofsteam from the highpressure cylinder.

a set of heating-pipes or other apparatus, L, which requires lowpressure steam. Being taken from the receiver H it is certain under allconditions to be at a moderate pressure above atmospherethat requiredfor steamheating and analogous purposes.

ure cylinder and all discharged into the receiver. ivettest particlesthrough the heater, and also such portion as is required is taken awayatv Next, it is dried by the passage of its the low pressure thereobtaining by the subi tractor-pipe K to be consumed in other uses thanpower. The remainder is utilized in the l low-pressure cylinder' only.

l is a pump, Worked by arod, t, from a lever,

(not shoWn,) which latter is operated by coni nections from the engine.

(Not represented.)

The stroke of the pump I may be made variable, if desired, to increaseor diminish the capacity of the pump. It is important that its capacityshould be sufeientto pump out all the waterwhieh ordinarily gathers inthercceiver at each stroke,and something over. The Water an d theaccompanying quantity of steam descends y through the pipe h, whichleads from the lowest point in the receiver H and rises through theindication-valve (not represented) into such pump, and thence it isforced by the Working of the pump past the eduction-valve into the fpipe D and through it into the heating appa! ratus B A B.

Where, as represented, the quantity of Water l has to be elevatedthrough the pipe D, a corresponding load is imposed on the pump I.

In situations Where it is practicable to carry the gaseous products ofcombustion down to a sufficiently low level the pump will have littleload, and may be dispensed with altogether,

and the Water in the receiver may move by gravity to the heatingapparatus B A B, or-

the equivalent set of heating parts, and willv the form of thoroughly.dried andsomewhat superheated steam. In this condition it reenters thereceiver and mingles with the damp contents therein, ready to be taken amoment later through the proper ports into the lowpressure engine.

The circulating-pump I has only to exert sufficient force to overcomethe gravity of the Water in forcing it up and the slight additionnecessary to overcome the friction. The pressure throughout the receiveran d its Whole train of connections is nearly uniformly moderate.

I take care to make the several pipes, es-

pecially the heating apparatus B AB, of snfficient strength to endure amuch greater pressure when required.

I provide means for using the heating apparatus B A B under the fullpressure of the boiler as a means for heating the feed-Water,

. and to some extent generating steam when K is a pipe leading from thereceiver H to desired.

P is a pipe bringing the relatively cold Water from the hot-Well underthe pressure of the feed-pump, (not represented,) which, of course,

is somewhat in excess of the boiler-pressure.

There are three conditions under which this 1 feed can be introducedinto the boilers, det-er- The steam is rst utilized in the high-pressjmined by the proper manipulation of the several stop-valves representedFirst, by opening the stop-valve Q, which controls the passage into theconnection Q, and closing the valve P', I can force the feed-Water inits primitive cold state through the connection Q into the pipe It, andthence up past the valves R directly into the several boilers. To dothis it will be understood that the valves Q' P and W V must be closed.This is the simplest mode of supplying feed to-the boiler, but obviouslythe least desirable in practice. It is important to raise thetemperature of the feed before introducing it into the boiler.

The second mode of feeding is the one which I prefer. The provision forheating the feed When thus Working is only a more or less liberal set ofadditional heating apparatus, marked U, which preferably lie near andreceive the spent heat from the boilers after they have imparted all theheat they may to the h eatin gapparatusB AB. Iopen the stop-valvePandclose the stopvalve Q. This prevents the water from flowing throughthe connection Q, and compels it to move through the pipe T and throughthe feed-lieating apparatus U. It 'thence flows in a heated conditionthrough the pipe V, and f l descending passes the valve V into thefeedpipe B, from whence it is delivered past the regulating-valves Itinto the respective boilers M.

.In the third mode of operating the feed the circulating-pump I isstopped and the receiver H is not drained of its Water and the sameevaporated, as thereby provided. Various causes may induce this thirdmode of Working. One would be by a fracture or derangement of thecirculating-pump I and its connections, which would compel thediscontinu.-

ance of the circulation. In such case the water collecting in thereceiver would have to be disposed of in the ordinary manner, by beingtrapped out or being allowed to accumulate until the bottom of thereceiver is full, and then being carried up by the current of steam andworked through the valves of the lowpressure engine, in which case Ithrow the circulating-pump I out of Lise, and work the feed as now to bedescribed, so as to increase the temperature of the feed and deliver itat the full boiler-temperature, or, still better, partly changed intosteam. This third mode works the feed-water through not only its properheater V, but also through the heating apparatus B A B.

It is well-always to keep water or water and steam from some sourcemoving through all the heating apparatus. The chances of these partsbecoming very greatly overheated is slight, but I believe it promotestheir endurance to keep all cool by a movement of fluid through them ata moderate temperature.

To work the feed in this third manner, the feed-water moves up throughthe pipe T, and becomes warmed in the feed-heater U, as before. Itthence flows out into the pipe V, as before, but is prevented frommoving down therein. I effect this by opening the valve Y' and closingthe valve V. The consequence of this is that the water in the lowestpart of the pipe V becomes stagnant, and the feedwater, passing thevalve Y', moves down through the pipe Y into the pipe D. The main partof the pipe D becomes lled with water, which stands idle, and thepartially-heated feed coming down through the pipe Y rises through theshort pipe W into our heater B A B. This heater is now subjected to thefull boiler-pressure. The feed-water becomes further heated in itspassage through this liberally-heated surface, and is delivered throughthe pipe E with the proper high temperature. Descending through the pipeE, it finds the stop-valve Z, controlling the short connection Z, open,and the stop-valve E closed. It consequently passes through Z into thepipe Q, and, through the latter, flows freely into the pipe B, anddelivers its hot feed water past the valves It into the boilers M withthe same effect as before, but at a still higher temperature.

Various modifications may be made in the form of the receiver and of theheating apparatus, as also of the pump and the means of operating thelatter.

The stop-valves may be differently arranged and still attain the wholeor an important part of the benefit due to my invention.

Additions may bem ade. For example, apipe (not represented) controlledby an adjustable valve or by a steam-trap may bring water, or mingledwater and steam, from steam-jackets on the cylinders, and allow such tomingle with the contents of the receiver H, and be subjected to theevaporative treatment in the heating apparatus BA B. I have, however,represented the apparatus as bringing the water from the steam-jacketsthrough a pipe, X, into the pipe or cross-connection Q, being understoodas delivered from the jackets (not represented) through a steam-trap.(Not represented.) It mingles with the water in pipe Q, and is thusreturned to the boilers.

I claim as my inventionl. The receiver H and its connections fg, leadingfrom' the two cylinders of a compound engine, in combination with theheating apparatus B A B, connected by circulating-pipes, as hereinspecified.

2. The circulatin g-pump I and its operating means,in combination withthe receiver H and pipes f g, connecting withv the high and low pressurecylinders of a compound engine, and with the heating appa-ratus B A B,adapted for joint operation, as and for the purpose herein specified.

3. The combination of the steam-receiver I-I with the two cylinders of acompound engine, and with the heating apparatus B A B, and with thesubtractor K, as and for the purposes herein specified.

4. The heating apparatus B A B, pipes D E, receiver H, and pump I, withsuitable operating means for the latter, in combination with additionalpipes and controlling-valves Y Y V Z, which allow the whole oftheheating apparatus to be used for heating feed-water, if desired,substantially as and for the purposes herein described.

In testimony whereofI have hereunto set my hand this 16th day ofOctober, 1878, in the presence of two subscribing witnesses.

eno. n. ooRLrss.

Witnesses J EREMIAH MILLER, En. W. RAYNsFoRD.

